The corrosion and erosion of mild steel were studied in water containing 3% sodium chloride with the relative velocities of 10-18m/sec at 30°C, by using high-speed rotor test apparatus.
The results obtained were summarized as follows:
(1) The corrosion rates of mild steel increased markedly in moving condition as compared with stagnant one, whereas it did not increase in spite of the increase of velocity from 10 to 18m/sec in the pH range 7-10. (2) There is a maximum of corrosion rates at pH 8-9 in moving condition. (3) The corrosion rates increased markedly by sand particles contained in the solution, and the erosion that could not be eliminated by cathodic current also occurred. (4) The sand erosion with a relativee velocity of 10-18m/sec is considered to be mainly of mechanical nature.

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Microphotographic study of corrosion products of copper in pure water were conducted. And some mechanisms and conditions of yielding corrosion products were discussed.
Corrosion tests were carried out using corrosion test loops at the temperature range of 40-90°C.
As the result, corrosion products were classified as follows:
(1) Yellow coloured acicular corrosion products.
(2) Yellow corrosion products as loam.
(3) Red and violet corrosion products.
(4) Black corrosion products.
By X-ray diffraction and reflectance spectra, predominant component of yellow and red corrosion products was identified with Cu₂O, and that of black corrosion products was CuO.
Mechanisms and conditions of yielding each corrosion products are supposed as follows:
(1) Yellow corrosion products (Cu₂O) are produced by decomposition of CuO under the condition where partial pressure of oxygen is very low and water is rather alkaline.
Acicular crystals grow out of black corrosion products (CuO) which exist under acicular crystals. In detail, CuO dissolve once in water surrounding it, and deposit acicular crystals (Cu₂O), like growth of ice needles, by reduction.
Yellow loam-like corrosion products are formed by direct decomposition of CuO in solid state.
(2) Iced corrosion products (Cu₂O) are yielded under the conditions where water is slightly acidic and/or partial pressure of oxygen is extremely low. These corrosion products have the tendency to peeloff.
(3) Black corrosion products.
Black loam-like corrosion products whose shape is same as yellow one, hemispherical corrosion products and others were observed.
These are produced under the high oxygen partial pressure generally. Hemisperical corrosion productsand loam-like corrosion products are produced at low temperature, low water velocity and high temperature, high velocity respectively. It seems that black loam-like corrosion products and yellow one change into each other easily with the change of conditions.

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The titanium specimen, which absorbed deuterium during corrosion in a DCl-D₂O solution, was irradiated with the accelerated deuteron of 10-150keV from the Cockcroft-Walton accelerator, and the amount and distribution of the absorbed deuterium were determined by counting the number of neutron emitted by the ²D(d, n)³He reaction. The relationship between the deuterium distribution and the neutron count-deuteron energy characteristics derived based on the data of the cross-section of the above reaction and the deuteron range given by Arnold and the others was consistent with the observed results. The proposed method can elucidate the amount of saturation and the approximate diffusion constant of deuterium in the surface region within the depth less than 1 micron.

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